how does sunscreen protect the skin from harmful u 5692205

ATI TEAS 7

ati teas 7 science

1. How does sunscreen protect the skin from harmful ultraviolet (UV) rays?

A. By reflecting UV rays away from the skin
B. By absorbing UV rays and converting them to heat
C. By blocking UV rays completely
D. By stimulating melanin production

Correct answer: B

Rationale: Sunscreen works by absorbing UV rays and converting them to heat. This mechanism helps to prevent the UV rays from penetrating the skin and causing damage such as sunburn, premature aging, and skin cancer. Reflecting UV rays away from the skin (option A) is not the primary function of sunscreen. While sunscreen does block UV rays, it does not do so completely (option C) as some UV rays may still penetrate the skin. Sunscreen does not stimulate melanin production (option D) as a means of protecting the skin from UV rays.

2. Which of the following sentences contains a colloquialism?

A. The Centers for Disease Control and Prevention is pretty sure that the Zika virus is spread through mosquito bites.
B. Travelers who are pregnant or considering pregnancy should consult a doctor.
C. Some theories on the Zika virus are difficult to understand.
D. In response, the U.S. has taken steps to prevent the spread of the Zika virus.

Correct answer: A

Rationale: The correct answer is A because the phrase 'pretty sure' is a colloquialism, making the sentence less formal. Choice B is incorrect as it is a formal recommendation. Choice C is incorrect as it contains no colloquial expressions. Choice D is incorrect as it is a straightforward statement without colloquial language.

3. Which sentence uses the semicolon correctly?

A. The play was long; however, it was very entertaining.
B. The guests arrived; Sarah greeted them at the door.
C. John likes apples; Mary prefers oranges.
D. He was tired; he went to bed early.

Correct answer: B

Rationale: Option B correctly uses a semicolon to join two independent clauses related to the same event. In this sentence, 'The guests arrived' and 'Sarah greeted them at the door' are both independent clauses that are appropriately connected using a semicolon. Choice A incorrectly uses a semicolon before 'however,' which is a conjunction that should be preceded by a comma. Choice C incorrectly uses a semicolon to connect two independent clauses that are not closely related. Choice D incorrectly uses a semicolon to connect two independent clauses without a clear relationship or cohesion.

4. A rocket engine expels hot gases backwards. What principle explains the rocket's forward motion?

A. Newton's first law of motion
B. Newton's second law of motion
C. Newton's third law of motion
D. Law of conservation of energy

Correct answer: C

Rationale: Newton's third law of motion states that for every action, there is an equal and opposite reaction. In the case of a rocket engine expelling hot gases backwards, the action is the expulsion of gases, and the reaction is the forward motion of the rocket. The hot gases being expelled act as the action force, propelling the rocket in the opposite direction as the reaction force, resulting in the rocket's forward motion. Newton's first law of motion (Choice A) pertains to inertia, stating that an object in motion will stay in motion unless acted upon by an external force. Newton's second law of motion (Choice B) relates force, mass, and acceleration, which is not directly applicable to the scenario of a rocket engine propulsion. The law of conservation of energy (Choice D) is a fundamental principle stating that energy cannot be created or destroyed but can only be transformed, which does not directly explain the forward motion of the rocket in this context.

5. How many milliliters are in 2 liters?

A. 2000 mL
B. 20,000 mL
C. 200 mL
D. 2 mL

Correct answer: A

Rationale: There are 1000 milliliters in 1 liter, so 2 liters equal 2000 milliliters. The conversion is based on the fact that the prefix 'milli-' means one-thousandth. Therefore, the correct answer is 2000 mL. Choice B, 20,000 mL, is incorrect as it multiplies 2 liters by 10. Choice C, 200 mL, is incorrect as it divides 2 liters by 10. Choice D, 2 mL, is incorrect as it incorrectly assumes that 2 liters is equal to 2 milliliters.